Combination bridging plug and combustion chamber



V. D. HANES A ril 17,1962

COMBINATION BRIDGING PLUG AND COMBUSTION CHAMBER 3 Sheets-Sheet 1 FiledJuly 22, 1957 INVENTOR. mus/141v DEA/V HANES 2 m 1 ATTORNEY April 17,1952 v. D. HANES 3,029,873

COMBINATION BRIDGING PLUG AND COMBUSTION CHAMBER ATTORNEY v. D. HANES3,029,873 COMBINATION BRIDGING PLUG AND COMBUSTION CHAMBER April 17,1962 3 s m M W, e T h N Y E M M S M E R D 0 w N n m V U M A 3 R; v 3; 91w Y r N 5 p Km? N v vm .v U 31 mg m m. my 21 mm;

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United rates Patent 3,02%,873 COMBHQATIQN ERHDGTNG PLUG ANDUZBP/ihUSTEGN CHAMBER Vaughan Dean Hanes, West Covina, Calih, assignorto Aerojet-General Corporation, Azusa, Califi, a corporation of )hioFiled July 22, 1957, Ser. No. 673,344) 14 fl-aims. (Cl. 166-63) Thisinvention relates to oil well tools. More particularly, the inventionrelates to oil well bridging plugs of the type which are run into a wellon a wire line and then expanded and locked into position by means ofhigh pressure gas generated by the burning of propellants in a closedchamber.

The invention described herein is a modification of the inventiondescribed and illustrated in my copending patent applications filedsimultaneously herewith, Serial Nos. 673,339, 673,260 and 673,298.

Bridging plugs are employed in oil wells for the purpose of forming abarrier in the well bore. The barrier may be either permanent ortemporary, and may be located either in the well casing or in theunc-ased portion of the well bore. The barrier, thus formed, serves toseparate the well bore into upper and lower sections which are isolatedfrom each other. A pressure differential may exist across the bridgingplug and may vary from a few pounds per square inch to several thousandpounds per square inch.

The bridging plug of the present invention is intended for use primarilyin those cases where the pressure ditferential is high across thebridging plug.

Heretofore, it has been the practice, when establishing a high pressurebarrier in a well, to employ bridging plugs which are relatively largeand which therefore contain large amounts of metal which must be drilledup when it is desired to remove them from the well. Such bridging plugsare relatively complicated and expensive to manufacture.

It is an object of the present invention to provide a high pressurebridging plug which is relatively small, simple in construction andcheap to make.

Another object is to provide a bridging plug and propellant combustionchamber combination adapted to be attached together to form a gaspressure setting bridging plug arrangement.

In recent years the method of setting bridging plugs Formerly, the plugswere run into the well on drill pipe or tubing, necessitating the use ofa derrick and rotary drilling equipment at a cost sometimes of severalthousand dollars, for the entire job. In recent years, the developmentof propellantactivated setting tools has made possible the running ofthe bridging plugs on a wire line instead of on pipe with a consequentlarge savings in expenses.

It is an object of the present invention to provide a bridging plug ofthe propellant-activated type, for wire line operation.Propellant-activated bridging plugs of the high pressure type, asheretofore constructed, required the use of separate, detachable settingtools containing the'propellant-activated mechanism which adds to thecost and expense of setting the plug.

It is an object of the present invention to provide a high pressurebridging plug of the wire line type which requires a separate combustionchamber but does not require a separate setting tool and thus reducesthe cost of setting the plug.

Other objects and advantages will be apparent from the followingdescription and drawings disclosing several embodiments of theinvention.

FIGURES 1a and 1b show in longitudinal section one embodiment of theinvention in the running in position.

The left hand end of FIGURE 1b showing a wire line running to thesurface, and the left hand end of FIGURE 1a being a continuation ofFIGURE 1b.

FIGURE 2 shows the parts of FIGURE 1a set in an oil well casing.

FTGURE 3 shows in longitudinal section a modified form of the inventionin which the lower end of the bridging plug is equipped with only oneset of slips.

FIGURE 4 shows the parts of FIGURE 3 set in an oil Well casing.

Referring to FIGURE 1, the numeral 1 indicates a well casing, Disposedwithin the well casing 1 and supported by a wire line 2, is a bridgingplug 3 and a combustion chamber 4, in the running-in position.

The bridging plug 3 comprises six major parts which are movable relativeto each other. These parts are: a piston 5, a cylinder 6, a floatingsleeve 7, a floating body 8, upper and lower wedge slips 9, and acompressible packer sleeve 10. The piston 5 and cylinder 6 constitute atelescopic housing on the exterior of which the well wall engaging partsare mounted.

a The combustion chamber 4 comprises three major parts not movable inrelation to each other. These parts are upper plug 11, lower plug 12,and combustion cylinder 13.

The piston 5 is formed in two parts, the lower member being provided atits lower end with an enlarged head 14 forming annular shoulder orabutment 14a, and a recess body 15 and an upwardly extending cylindricalshank 16 of reduced diameter, to which is connected as by the threads17, an enlarged tubular upper piston member 18 a peripheral shoulderbeing thus formed between shank 16 and upper piston member 18.

The cylinder 6 is slidably mounted on the shank 16 and piston member 18.To this end, the cylinder 6 is provided with a tubular lower portion 19which slidably engages the outer surface of the piston member 18 and hasan inwardly turned flange 20 at its lower end slidably engaging theexterior surface of the tubular shank 16.

A suitable sealing means, such as the 0 rings 21, are mounted in theflange 20 in sealing relation with the exterior surface of the shank 16.The upper portion of the cylinder 6 is enlarged as indicated at 2-2 toprovide a downwardly facing annular shoulder or abutment 23 againstwhich the upper wedge slips 9 are supported in their retracted position,as shown in FIGURE 1. The interior'of the cylinder 6, above the flange20, which slidably engages the exterior surface of the piston 5, forms apressure or expansion chamber 24 below the lower end of the upper member18 of the piston. Sealing means, such as the O ring 25', is positionedin the exterior surface 'of the piston member 18 in sealing engagementbetween the walls of the cylinder 4 and the piston member 18.

The floating sleeve 7 is tubular in form with its interior surface, asindicated at 26, in slidable engagement with the exterior surface of theenlarged head 14 and its interior surface, as indicated at 27, inslidable engagement with the exterior surface of the tubular portion 19of the cylinder 6. The lower outer portion of the floating sleeve 7 istapered downwardly and inwardly to form a frusto conical seat 28 for thelower wedge slips 9. The lower wedge slips are normally held in theirretracted position, supported by the shoulder 14a, by any suitablemeans, such as shear pins 29 attached to the floating sleeve 7 asindicated in FIGURE 1.

The upper end of the floating sleeve 7 terminates in an upwardly facingannular shoulder seat 30 which serves as a seat for the lower end of thecylindrical, resilient packer sleeve 10.

The floating body 8 is tubular in form with its interior surface 31 inslidable engagement with the exterior surface of the cylinder 6. Theupper outer portion of the floating body 8 is tapered upwardly andinwardly to form a frusto conical seat 32 for the upper wedge slips 9.The upper wedge slips are normally held in their retracted position, byany suitable means, such as the shear p1ns 33 attached to the floatingbody 8.

The lower end of the floating body 8 terminates in a downwardly facingannular shoulder seat 34 which serves as a seat for the upper end of thecylindrical, resilient packer sleeve 10.

In order to lock the cylinders 6 and piston in the set position, theouter surfaces of piston member 18 is provided with a series ofvertically spaced, downwardly facing teeth 35. The teeth 35 are adaptedto engage a series of vertically spaced, upwardly facing teeth 36 formedon the inner face of the wedge locks 37 mounted in recess 38 formed inthe upper end of the cylinder 6. The bearing wall 39 of the recess 38 istapered downwardly and inwardly. A compression body of any suitablematerial, such as an 0 ring 40, is mounted in the recess 38 between theupper surface of the wedge locks 37 and the lower surface of a retainerplate 41. The retainer plate 41 is attached to the cylinder 6, by anysuitable means, such as the screws 42.

The cylindrical resilient packer sleeve is mounted between the shoulderseats 30 and 34 and has its interior surface in slidable engagement withthe exterior surface of the cylinder 6.

The piston member 18 is provided with the axial hole 43 and at its upperend with the transverse holes 44 (FIG. 2).

The shank 16 is provided with the counterbores 45 and 46, the hole 47and the transverse holes 48. A screen, such as the plate 49 with itsholes 50 may be placed between the lower surface 51 of the member 18 andthe upper surface 52 of the shank 16.

Referring to FIGURE 1, the combustion chamber 4 is provided at its upperend with a reduced diameter to which is connected the union nut 53 bythe threads 54. The cylindrical upper plug 11 is provided with the uppershank 55, the lower shank 56, the flange 57 between the upper shank 55and lower shank 56, and the axial hole 58 in which is mounted theinsulated electrical connection device 59. The wire line cable head 60,of a suitable type, details not shown, is attached to the upper end ofupper shank 55 by the threads 61. The lower shank 56 of the upper plug11, is adapted to fit into the axial bore 62 provided in the combustioncylinder 13. A suitable sealing means, such as the O ring 63, is mountedon the lower shank 56 in sealing engagement with the interior surface64, formed by the bore 62, of the combustion cylinder 13.

The upper plug 11 is attached to the combustion cylinder 13, by means ofits flange 57, union nut 53 and the threads 54. The upper plug 11 can beremoved from the combustion chamber 4 by unscrewing the threads 54.

The electrical connection device 59, is mounted in the axial hole 58 ofthe upper plug 11, and consists of the tubular insulating material 65mounted within the axial hole 58 and supported between theinsulating-sealing washers 66 and 67 and retained in place by means ofsupport washers 68 and 69, the electrical rod 70, the lower enlargedhead 71 of the rod 70, and nut 72 on threads 73 at the upper end of rod70. The electrical rod 70 passes through the axial hole in the tubularinsulating material 65, the holes in the insulating-sealing washers 66and 67, and the holes in the support washers 68 and 69. Theinsulating-sealing washers 66 and 67 are mounted in countersunk bores 74and 75 provided in the upper plug 11. The electrical connecting device59 seals the axial hole 58 by means of the tubular insulating material65 and the insulating-sealing end washers 66 and 67 being compressed andexpanded between the support washers 68 and 69 by means of the rod 70,the enlarged head 71, the nut 72 and the thread 73.

The insulated electric cable 76 is clamped against nut 72 on the rod 70by means of the nut 77. The electric 4 cable may extend to the surfaceby any suitable means such as the wire line 2.

The combustion chamber 4 is provided at its lower end with the lowerplug 12. The lower plug 12 has the upper shank 78 adapted to fit intothe axial bore 62 and to seal said bore 62 by means of suitable sealingmeans, such as the 0 ring 79. The lower plug 12 also is provided withthe downward extending shank 80 having flange 81 located between theshank 78 and 80. The lower plug is attached to the combustion cylinder13 by means of the threads 82.

The upper surface of the shank 78 is provided with the counterbore 33 inwhich may be mounted a screen, as indicated by the body 84, havingscreen holes 85, The lower plug 12 is provided with an axial passageway86. The extending shank 80 is adapted to fit into the axial hole 43 ofthe piston member 18. Sealing means such as the 0 ring 87 is mounted inthe exterior surface of the extending shank 89 in sealing engagementbetween the walls of the piston member 18 and the shank 80.

The combustion chamber 4 is slidably and shearable connected to thebridge plug 3 by means of the shear pins 38 and the shoulders 89provided in the extension shank 86 of the combustion chamber 4.

A charge of gas generating propellant grain 90 is positioned in theaxial bore 62 of the combustion cylinder 13 between the upper plug 11and the lower plug 13. An electric igniter of any suitable type such asthe squib 91, is positioned in the lower end of the propellant grain 90and retained in place by the plug 92. The insulated lead 93 of the squib91, is connected to the enlarged head 71, of the rod 70, by any suitablemeans such as the wraps 94 around the head 71 and the ground lead 95 ofthe squib 91 is grounded to the combustion chamber 4, by any suitablemeans, such as the screw 96 to complete the electric circuit. Aresilient means, such as the spring 97 may be used to support thepropellant grain 90 above the screen body 84.

The propellant grain 90 consists of a cylindrical gas producingpropellant 98 in which is mounted the squib 91. A quantity of ignitermaterial 99, such as a mixture of black powder and magnesium may beplaced between the propellant 98 and the squib 91 to assist in ignitionof the propellant grain 90. The propellant grain 90 is provided with theexternal covering 100 to prevent burning of the propellant on any othersurface than its lower end to produce an end burning grain. The combinedvolume of the bore 62, the counterbore 83, the passageway 86, the hole43, the counterbore 46, the hole 47, the communicating transverse holes48 and the pressure chamber 24 from a closed fiuid chamber within theintelrioro, of the combustion chamber 4 and the bridging P FIGURE 2illustrates the bridging plug of FIGURE 1 in a set position in the wallcasing 1. Upon application of electrical current, from any suitablesource such as a wire line service unit, the electric squib 91 is fired,igniting the igniter material 99 and initiating the burning of thepropellant 98.

The gas pressure generated by the burning of the propellant grain 90within the combustion chamber 4 causes the cylinder 6 to move downwardlyon the shank 16 of the piston 5, and in so doing shears the pins 33 and29, releasing the upper and lower wedge slips 9. Continued downwardmovement of the cylinder 6 with respect to the piston 5 pushes thefloating sleeve 7 and the floating body 8 downwardly. The compressiblepacker sleeve 10, being restrained between the shoulders 30 and 34 iscompressed and expanded laterally until packer sleeve 10 is tightlyengaged with the inner wall 101 of the casing 1 as indicated in FIGURE2. At the same time, downward movement of the cylinder 6 in respect tothe piston 5, forces the upper and lower wedge slips 9 into contact withthe inner surface 101 of casing 1 due to movement on the frusto conicalseats 28 and 32. Also, at the same time, downward movement of thecylinder 6 in respect to the piston causes the teeth 36 of the wedgelock 37 to engage the teeth 35 of the piston member 18 to lock thecylinder 6 against any subsequent upward movement, and thus maintainingthe packer sleeve in sealing engagement with the well casing 1.

Continued build-up of pressure will cause the shear pins 88 to shear,thereby releasing the combustion chamber 4 from the bridging plug 3 andreleasing the gas pressure from the bridging plug 3 and the combustionchamber 4.

The expanded packer sleeve 10 together with the expanded upper and lowerslips 9 will enable the bridging plug 3 to withstand high difierentialpressures in either direction.

The shearing of the pins 88 releases the combustion chamber 4 and thewire line 2 from the bridging plug. The wire line 2 and combustionchamber 4 may be removed from the well.

. FIGURE 3 illustrates a variation of the bridging plug shown in FIGURES1 and Z'Which has two sets of wedge slips 9, these being so positionedas to prevent movement in either direction in the well casing -1.Sometimes, a bridging plug is used to support pressure in the downwarddirection only. In this case it is customary to provide the bridgingplug with only one set of wedge slips toprevent downward movement of theplug in the casing.

Referring to FIGURE 3, the numeral 120 indicates a single slip bridgingplug, in the running-in position, disposed within the oil well casing 1and supported on a wire line not shown. The bridging plug 120 comprisesfive major parts which are movable in relation to each Other. Theseparts are: a piston 121, a cylinder 122, a

, floatingbody 123, wedge slips 124, and a compressible packer sleeve125.

The piston 121 is provided at its lower end withan enlarged head 126forming an upwardly facing annular shoulder 127, a recessed body 128having an upwardly extending shank 129 of 'still further reduceddiameter to which is connected, as by the threads 130, the piston member121.

The cylinder 122 is slidably mounted on the shank 129 and the pistonmember 121. To accomplish this, the cylinder 122 is provided with atubular lower portion 132 which slidably engages the outer surface ofthe piston member 131 and has an inwardly turned flange 133 at its lowerend, slidably engaging the exterior surface of the shank 129. Suitablesealing means such as the 0 rings 134, are mounted in the flange 133 andthe 0 rings 135 are mounted in the piston member 131 to form anexpansion chamber 136. The upper end of the cylinder 122 is providedwith the enlarged head 137 forming a downwardly facing shoulder seat137a that serves as a seat for the upper end of the resilient packersleeve 125.

The floating body 123 is tubular in form with its inten'or surfaces 138in slidable engagement with the exterior surface of the tubular body 128and its interior surface 139 in slidable engagement with the exteriorsurface of the cylinder 122. The lower portion of the floating body 123is tapered downwardly and inwardly to form a frusto conical seat 140 forthe wedge slips 124. The wedge slips 124 are normally held in theirretracted position, resting on the shoulder 127, by any suitable means,such as the shear pins 141, attached to the piston 121.

The upper end of the floating body 123 terminates in an upwardly facingannular shoulder 142 which serves as a seat for the lower end of theresilient packer sleeve 125. The locking arrangement is similar to thatdescribed for the bridging plug of FIGURE 1. Fluid passageways are alsoprovided in the plug of FIGURE 3 similar to those of the plug of FIGURE1.

A combustion chamber device 143, similar to the combustion chamber 4 ofFIGURE 1, is attached by shearable means not described to the bridgingplug 120 as indicated at the numeral 144.

FIGURE 4 illustrates the device of FIGURE 3 in set .position in the wellcasing 1. High pressure gas supplied by the combustion chamber 143 intothe expansion chamber 136 causes the cylinder 122 to move downwardly inrelation to'the shank 129 and in so doing shears the pins 141, releasingthe wedge slips 124. Continued downward movement compresses theresilient packer sleeve 125 between the shoulders 137a'and 142 andexpands it into sealing engagement with the casing 1 and in sealingengagement with the exterior surface 145 of the cylinder 122. At thesame time, continued gas pressure build-up in the combustion chamber 143and bridging plug sets the wedge slips 124 into the casing 1 and shearsout the retaining means to release the combustion chamber 143 from theplug 120. The locking means retainslthe bridging plug in the setcondition.

When fluid pressure is applied to the casing -1 above the set bridgingplug of FIGURE 4, the fluid is prevented from flowing downward in thecasing 1 due to the sealing of the packer sleeve against the interior ofthe casing 1 and due to the holding action of the wedge slips 124 intothe casing 1. I

The exterior surface 145 of the cylinder 122 forms a piston rod typeengagement with the interior surface of the packer sleeve 125.Application of pressure to the upper side of thecasing sealing means ofthe bridging plug causes the packer sleeve 125 to be compressed and 125.Therefore, the bridging plug is pressure responsive after being set andthereby automatically increases its sealing engagement with the casing,

I claim:

1. Well apparatus comprising: a piston, a cylinder slidably receivingsaid piston,'a plurality of wedge slips surrounding said piston and saidcylinder, a first means for supporting one of said wedge slips attachedto said cylinder, a second means for supporting one of said wedge slipsattached to said piston and extending through said cylinder, a packersleeve surrounding said cylinder and positioned between said wedgeslips, a plurality of means for expanding said wedge slips surroundingsaid cylinder and positioned between said wedge slips and said packersleeve, said piston having a passageway therethrough in communicationwith said cylinder, means for generating a fluid positioned remote tosaid piston and cylinder, and a means for providing a passageway forfluid attached to said fluid generating means and said piston and incommunication with the piston passageway and said fluid generatingmeans.

2. Well apparatus as defined in claim 1 and in addie tion: means forlocking attached to said piston and said cylinder, said locking meansused to prevent movement in a direction reversed to that desired.

3. Well apparatus as defined in claim 1 and in addition: a shearable pininterconnected to said passageway means and said piston.

4. Well apparatus as defined in claim 1 wherein said fluid generatingmeans comprises: means for forming a combustion chamber, a solidpropellant arranged in said chamber forming means, means for ignitingsaid propellant arranged in said chamber forming means.

5. Well apparatus as defined in claim 1 and in addition: a means forattaching said passageway means to said piston and connected thereto.

6. Well apparatus comprising: a piston, a cylinder slidably receivingsaid piston, said cylinder having an inwardly extending flangecontacting said piston, an enlarged head attached to said piston andextending exacaaeva ternally of said cylinder past said cylinder fiange,said cylinder having an outwardly extending enlarged portion thereon,wedge slips circumscribing said piston and said cylinder and abuttingsaid enlarged head and cylinder enlarged portion, a packer sleevecircumscribing said cylinder and positioned between said wedge slips,means for expanding said wedge slips positoned between said wedge slipsand said packer sleeve, said piston having a passageway therethrough incommunication with said cylinder, means for generating fiuid positionedremote to said piston and said cylinder, and a means for providing apassageway for fluid attached to said fluid generating means and saidpiston and in communication between said fluid generating means and saidpiston passageway.

7. Well apparatus as defined in claim 6 and in addition: means forlocking attached to said piston to said cylinder, said locking meansused to prevent movement and direction reversed to that desired.

8. Well apparatus as defined in claim 6 wherein said fluid generatingmeans comprises means for forming a combustion chamber, a solidpropellant arranged in said chamber forming means, and means forigniting said propellant arranged in said chamber forming means.

9. Well apparatus as defined in claim 6 and in addition: a shearable pininterconnected to said passageway means and said piston.

10. Well apparatus as defined in claim 9 in which the sliearable pin isconstructed of a material that will shear at a pressure greater thanthat required to set the slips and sleeve packer.

11. Well apparatus comprising: a piston consisting of a tubular member,an enlarged head having a cylindrical shank attached to said pistontubular member, a cylinder slidably receiving said tubular member, saidcylinder having a flange extending radially inwardly in contact withsaid cylindrical shank, said tubular member having a port thercthroughpositioned adjacent the said cylindrical shank thereby having theinterior of said piston tubular member in communication with saidcylinder, said cylinder havingan enlarged portion extending radiallyoutwardly, wedge slips circumscribing said cylinder and said cylindricalshank and abutting said cylinder enlarged portion and said enlargedhead, an annulus shaped packer sleeve circumscribing said cylinder andpositioned between said wedge slips, a means for expanding wedge slipspositioned between said sleeve packer and said wedge slip, a means forgenerating fiuid remotely positioned in relation to said tubular memberand cylinder and a means for providing a passageway attached to saidfluid generating means and said tubular member and in communication withsaid fluid generating means and said tubular member port.

12. Well apparatus as defined in claim 11 and in addition means forlocking attached to said tubular member and said cylinder to preventmovement in a direction reverse to that desired.

13. Well apparatus as defined in claim 11 wherein said fluid generatingmeans comprises means for forming a combustion chamber, a solidpropellant arranged in said chamber forming means, and a means forigniting said propellant arranged in said chamber forming means 14. Wellapparatus as defined in claim 11 and in addition a shearable pininterconnected between said passage way means and said tubular memberconstructed of a material which will shear at a pressure greater thanthat required to set the wedge slips and the sleeve packer.

References Cited in the file of this patent UNITED STATES PATENTS2,262,117 Roe Nov. 11, 1941 2,266,382 Quintrell et al Dec. 16, 19412,308,004 Hart Jan. 12, 1943 2,618,343 Conrad Nov. 18, 1952 2,640,547Baker et al. June 2, 1953 2,675,877 Baker Apr. 20, 1954 2,807,325 WebbSept. 24, 1957

